Instructions

1. Make the Levain: Weigh out the levain ingredients in a small bowl or jar (100g sourdough starter, 15g bread flour, 15g whole wheat flour, 5g rye flour, 35g water). Stir together, and leave at room temperature until very bubbly and doubled in size, about 5 hours.

2. Meanwhile, about 2 hours before the levain will be ready, perform the autolyse: Stir the 135g whole wheat flour, 365g bread flour, and 425g water together in a bowl. Let sit for about 2 hours. If levain is ready to use before the autolyse has gone a full 2 hours, proceed with mixing dough anyway.

3. Mix the dough: Weigh out 70g levain, and add to the top of the autolyse mixture of flour and water. Sprinkle salt around the edges. With damp hands, pull up and fold dough from edges to the middle, turning the bowl as you fold, until completely mixed. Cover; let rest for 15 minutes. Cover and return the excess levain to the refrigerator to use for a future batch of bread.

4. Perform first set of folds: Lift dough with wet hands at the edge and flop to the middle; turn the bowl a few inches and continue to flop and turn until dough begins to resist being pulled to the center. Repeat folds twice more, 15 minutes apart, covering dough in between.

5. Set a timer for 30 minutes. Now turn dough out onto counter, and perform the first stretch and fold. Stretch the dough into a rough 12-inch square. Pull 2 corners and fold the dough into thirds; then fold the top half to the bottom. Roll the dough forward, then form into a ball with a flat bench scraper; return dough to the bowl and cover.

6. Repeat the stretch and fold process 2 more times, 30 minutes apart. Cover; let dough bulk ferment until very bubbly and doubled in size, 4 to 5 hours.

7. Turn dough out onto counter, and pre-shape dough into a ball. Dust with flour, and let rest on the counter 30 minutes.

8. Perform the final shaping: Dust the counter with flour, and gently flop the dough over into the flour with the bench scraper. Again, perform a stretch and fold, but gently, to not deflate the dough. Shape into as high and round a ball as possible using the bench scraper. Dust the top with flour.

9. Generously dust a banneton with rice flour, Carefully slide the bench scraper under the dough, and turn it over into the banneton. Now, and this is optional, "stitch" the dough by bringing opposite pieces of the dough up, sticking them together in the center. Dust with a little flour.

10. Cover; proof dough in the refrigerator for 14 hours.

11. One hour before baking, place the pan you will bake the bread in, or a pizza stone, in the oven. and heat the oven to 500 degrees F (260 degrees C).

12. After 1 hour of preheating, turn dough out of banneton onto parchment, and score 1/4-inch deep with a lame, razor, or sharp thin knife. Place in bread pan, add 2 ice cubes to the pan; cover.

13. Bake for 20 minutes at 500 degrees F (260 degrees C). Remove cover, lower the heat to 450 degrees F (240 degrees C), and bake an additional 35 minutes, or until desired doneness.

14. Let cool 1 hour before slicing.